The present invention is related to systems and methods for disabling one or more cylinders in an internal combustion engine while other systems remain operational.
It is known in the auto industry that during different operational modes, different amounts of power are required. For example, at idle conditions compared to high performance conditions, different power is required from the engine. Since valves are typically controlled by cam systems which are generally fixed, compromises have been made which lean toward normal load or speed ranges. Thus, it is typical that excessive engine power is being produced at certain times, particularly during idle and other low power modes.
Various systems have been designed to compensate for different operational loads. For example in U.K. Patent Application GB 2 122 682 A, a multiple-displacement engine is disclosed. There, the number of operating cylinders changes according to the load by cutting off fuel supply to some cylinders. Specifically, the fuel injection control circuit cuts off the fuel to cylinders on a random or sequential basis, depending on engine load.
Additionally, in U.S. Pat. No. 5,035,220, a fuel controller is disclosed wherein a sensor detects misfiring in a cylinder. Thus, when the cylinder misfires, the fuel injector corresponding to the misfiring cylinder is prevented from supplying fuel to the misfiring cylinder. Though this is not designed to adjust itself based upon power requirements, the concept of shutting down a cylinder is practiced in response to malfunction.
In U.S. Pat. No. 4,991,558, the operation of a multiple cylinder two-stroke internal combustion engine is disclosed wherein the engine is operated at idle by interrupting the fuel injection stages in a predetermined pattern. Thus, over several crankshaft revolutions, fewer number of injections occur, saving fuel. Similarly, in U.S. Pat. No. 5,038,739, a multi-cylinder two-cycle engine is disclosed wherein fuel is injected and ignited at less than typical intervals. Thus, at least one piston stroke for each cylinder occurs during which no combustion takes place. Additionally, fresh air is pumped through the combustion chamber to scavenge residual combustion gases therefrom.
There have also been systems developed which completely disable the operation of certain valves during different modes of operation. In U.S. Pat. No. 4,111,165, the concept of changing the valve lift and valve timing of the intake and exhaust valves of an internal combustion engine is disclosed. Specifically, the intake and exhaust valves are maintained in a closed position during deceleration of the engine. Another example of such a design is the Cadillac 8-6-4 engine. This design utilizes very high powered solenoids in order to disable the valves and maintain their disabled state. However, such solenoids are very expensive and can become a dashpot that robs the rest of the engine of power. This is because constant power is required to maintain the solenoid activation.
Thus, with regard to the concept of completely disabling one or more cylinders, it would be desirable to provide an inexpensive system for disabling one or more cylinders in an internal combustion engine without sacrificing any significant amount of power.
The present invention provides systems and methods of disabling cylinders in an internal combustion engine. Specifically, a method of disabling at least one cylinder for at least one complete engine cycle in a multiple cylinder combustion engine is disclosed which comprises closing a fuel combustion air intake valve associated with at least one cylinder such that essentially no fuel enters the at least one cylinder, opening an exhaust valve associated with the at least one cylinder such that piston movement within the cylinder is essentially unimpeded, and allowing at least one complete engine cycle to occur while both the fuel combustion air intake valve is closed and the exhaust valve is open.
Additionally, a system for disabling at least one cylinder in a multiple cylinder combustion engine is disclosed. This system comprises a first rocker arm associated with opening and closing of a fuel combustion air intake valve wherein the first rocker arm has an operational position and a disabled position, a second rocker arm associated with opening and closing of an exhaust valve wherein the second rocker arm has an operational position and a disabled position, and a switch for toggling the first and second rocker arms from their respective operational positions to their respective disabled positions. The rocker arms (and thus the valves) are preferably disabled by a pair of auxiliary cams that can be rotated to effectuate this result.
Alternatively, a circuit for disabling power to an engine while maintaining power to other operational loads is disclosed. This circuit comprises an ignition switch and a plurality of parallel circuits electrically coupled to the ignition switch wherein the plurality of parallel circuits branch out from a common branched circuit region. A parallel spark plug power circuit branched from the common branched circuit region electrically couples the engine to the ignition switch. An interrupter switch is also positioned on the spark plug power circuit, between the branched circuit region and the cylinder or engine, for interrupting power to the engine without interrupting power to the plurality of parallel circuits.